The present invention relates to a process for recovering and separating uranium and molybdenum from a pregnant lixiviant by two-stage ion-exchange adsorption.
Uranium ore deposits which contain certain portions of other metals such as calcium, molybdenum etc. are selectively leached in-situ by passing through a relatively diluted carbonate/bicarbonate solution with oxidants such as oxygen and hydrogen peroxide. The solution withdrawn from the ore deposits will then contain uranium and various contaminants in their different ionic forms co-produced during uranium leaching with molybdenum being the most persistant contaminant. Uranium as well as molybdenum are recovered when the solution is brought into contact with a strong base anion-exchange resin which selectively adsorbs uranium and molybdenum.
Since both uranium and molybdenum are loaded on the anionic resin, and in most cases eluted altogether (although their elution efficiency may be different), a purification step(s) is required before a Mo-free uranium is produced.
Various methods are used for countering the molybdenum problem involving either some method of removing molybdenum from the process liquors or of treating resins in ion exchange methods and solvents in solvent exchange methods to rid them of excess molybdenum.
For example, separation of molybdenum from the uranium eluate can be accomplished by using a tertiary amine solvent at 3-3.5 pH. Molybdenum can also be selectively loaded onto an activated charcoal column thus producing a Mo-free uranium eluant for recovery.
The process of the present invention offers simplicity and economics as compared to the prior art techniques.